From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:60389 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751700Ab2LPUEs (ORCPT ); Sun, 16 Dec 2012 15:04:48 -0500 Date: Sun, 16 Dec 2012 20:04:46 +0000 From: Al Viro To: Paul Bolle Cc: Mauro Carvalho Chehab , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org Subject: Re: [PATCH] omap_vout: find_vma() needs ->mmap_sem held Message-ID: <20121216200446.GF4939@ZenIV.linux.org.uk> References: <20121215201237.GW4939@ZenIV.linux.org.uk> <1355688070.767.4.camel@x61.thuisdomein> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1355688070.767.4.camel@x61.thuisdomein> Sender: linux-media-owner@vger.kernel.org List-ID: On Sun, Dec 16, 2012 at 09:01:10PM +0100, Paul Bolle wrote: > > + vma = find_vma(mm, virtp); > > } else if (vma && (vma->vm_flags & VM_IO) && vma->vm_pgoff) { > > Shouldn't that line become > if (vma && (vma->vm_flags & VM_IO) && vma->vm_pgoff) { > > so that this actually compiles? *Do'h* Yes, it should. Mea culpa... Signed-off-by: Al Viro --- diff --git a/drivers/media/platform/omap/omap_vout.c b/drivers/media/platform/omap/omap_vout.c index 9935040..cb564d0 100644 --- a/drivers/media/platform/omap/omap_vout.c +++ b/drivers/media/platform/omap/omap_vout.c @@ -207,19 +207,21 @@ static u32 omap_vout_uservirt_to_phys(u32 virtp) struct vm_area_struct *vma; struct mm_struct *mm = current->mm; - vma = find_vma(mm, virtp); /* For kernel direct-mapped memory, take the easy way */ - if (virtp >= PAGE_OFFSET) { - physp = virt_to_phys((void *) virtp); - } else if (vma && (vma->vm_flags & VM_IO) && vma->vm_pgoff) { + if (virtp >= PAGE_OFFSET) + return virt_to_phys((void *) virtp); + + down_read(¤t->mm->mmap_sem); + vma = find_vma(mm, virtp); + if (vma && (vma->vm_flags & VM_IO) && vma->vm_pgoff) { /* this will catch, kernel-allocated, mmaped-to-usermode addresses */ physp = (vma->vm_pgoff << PAGE_SHIFT) + (virtp - vma->vm_start); + up_read(¤t->mm->mmap_sem); } else { /* otherwise, use get_user_pages() for general userland pages */ int res, nr_pages = 1; struct page *pages; - down_read(¤t->mm->mmap_sem); res = get_user_pages(current, current->mm, virtp, nr_pages, 1, 0, &pages, NULL);